Smooth and silky top end

Hi folks, I'm not a techie but does anyone know how you can get an extended but silky top end out of an solid state power amplifier? Design plays a of course a pivotal role: Could one achieve this silky top end by using negative feedback, mode of amplification (class A, class D)? Or is it a matter of execution: parts selection and matching, use of solely discrete parts (no OPamps), use of tubes (hybrid solid state/tube design)? I know you can achieve this goal by treble cut off or by softening of the treble using filters, cables or tweaks that soften treble response, but that is not what I mean. Btw, a known solid state reference for a silky and extended treble are the FM Acoustics power amplifiers (especially the 800A, a 40-year old design!).
This issue leads to the next question: Is a silky and smooth top end a characteristic of good amplification or is it in fact a form of coloration (softening of the treble by non linearities in the electronics). Amp designers are welcome to comment on these topics.

Chris